Automatic hood guard



Aug. 13, 1935. w. D. DRUMMOND 2,010,851 l AUTOMATIC HOOD GUARD Filed July 2 1934 s sheets-sheet 1 Aug. 13, 1935. w. D. DRUMMOND 2,010,851

AUTOMAT C `HOOD GUARD Filed July 2;'1934 s sheets-sheet 2 3 Sheets-Sheet 5 Filed July v2, 1934 M .2 5 w f w l |||l V o w o y 7 6 o@ 7 4/ 0 a 2 5 DIV! o n f h 5 A 5 fi guardzfarrangement which has a` certain amount Patented Aug. 13, 1935 VAU'rorIrll'rIo Hoon GUARD` William D. Drummond, olifrsiwde, N.- J. Application July 2, 1934, serial No. 733,399 e 9 claims. (c1. 143-.-159) My present invention relates to theart of `vaccident prevention,` and has particular reference to s hood guards for usewith circular saws.

The hood guards heretofore used for circular saws consist of afhood or "the like which rises when the Work is inserted,y but which aiords no protection for the ngers'of the operator, as the saw teeth are freeto be contacted by the operator both at the 7 point where the .saw emerges from the table and at the point where `the saw leaves' the table... It Ais",` the principal `object of my invention to provide an automatic hood guard Lwhich willfully protect itlie lingersk of the opertorvat "all".timell,` without interfering with` the nermal'pera'tion" ofthe `saw. e

The hood guards heretofore used have also been `disadvantageons in that no means have been provided for positivelyleliminating kick-back, Aas thekiek-back has two` causes, namely, pinching ofthe wrkafter it leaves the saw, and directbackward thrust of the `saw.` `Itisl ia further object of "my` invention to provide autematic `nneansyfor eliminating anyl kick-back, whether diieltopinching of 'thework or to engagement ofthe saw with the work. e e

further dmculty @und in hood guards', Darticularly of the stationary type. has resided inthe inabilit 0f the heed, guard t0 .more Qrfvield backwards. It istherefore an additional object of, rnvxt'linvention te 4provide an automatic hood efbackward yield ortravellunder `unusual cirfeatures when so movedf" i I'. have `further foundfit'desirable tor provide a z, cumstances, but does ynot lose its protective V` novel. locking arrangementwhereby thehood ofhanovel arrangement of parts more` fully disciosedin the` detailed descriptionfollowing, in

. conjunctionfwith the following drawingsand morejspecicallydened in the claims appended thereto. u l

J "I'he accompanying drawingsillustrate a preferred embodiment of my invention, like characters of'referenceindicating like parts throughout the views; "Figi 1is Ya side elevation showing a conventional saw` frame with the novel guard in operative position;

.having actuating mechanism of standard type.

Fig. is incomplete fragmentary-section mi thereof lon the line 2-g-2 of Fig. 1*; A I Fig. `3 is an enlarged plan View of.y thefgnard, the novel slide ng'els being shown in section; l, i Fig; 4 is a side elevation thereof ,on the line 4 4 IofFig.3; Q v Fig.4 51 is a detailed elevation of the novel spreader; f f Fig..6 is a detailed View showing thenovel locking attachment, and ,n gl. i Ffgs. 7, 8, and 9 are side elevations illustrating the operation of the novel guard parts during a sawing operation. i ,Y

It has been ioundladvisable to4 previde an automatic hood guard which effeetiveljpreyents{contactl of the `olineratofs` `ngers" withl. the" saw teeth through the entire sawing operation the .parts being so arranged that the saw teeth are not` uncovered or open atany time. Iihave therefore devised aA novel automatic .hood guard which` is quickly attached or detached, and which has members which preventengagement of the Voper-` atorsf ingers Awith :the saw teeth, while the work is i entering the` saw,r during `the sawing operation, andwhile leaving `thesaw..` Moreover, I have provided positivefmeans for preventing kick-baek of the work byiutilizing a spreaderlfor'keeping the bifnrcated saWed parts apart, anddogs which positively engage' the work so asto prevent rear.- ward movement thereof. i ,i p

"A preferred embodiment of my `invention-is illustratedin the drawings, in whichthe frame work I0 hastheiusiial tableflvlfa rock shaft I2H being suitably journaled in the frame `work Aand A bearing support I3 is keyed to `the rock shaft NT vOIFICE,

I2 and`has-spacedfbearingsld, see Fig. `2, for' the arbor I5 which carries thedr'iving pulley I6,

a belt `Il of standard type passing around guide rolls [8 and I9 .and supplying power fordriving the' arbor 'iythusrotating the saw? ttl which is keyed thereto.` The arbor hasthe usualfstandard mechanism forladjustment and` forlocking the saw `on the spindle, including ball bearing races, such jaslfor example shown in'my-'previousPatent No.1,711,490, and has a collarl `2l mounted thereon ".forreceiving the hub 2'2 `of apivot arm 2,3, s 'ee Fig.` ,5, which `has itsend engageable with the lower Asurface of the table, a tension spring lM :connecting this arm ,to a similar arm `2li also having rahub 26rotatablymounted on the col-f` lar, the arm 25 having anl arcuatef spreader `2l secured at its free end whichnormallyv projects above Vthe table so' as to overhang the rear end of the saw a short distance away-from the saw teeth. The spreader is of the same width as the saw and in alignment therewith, and functions to maintain the cut portions separated, thus effectively preventing pinching of the work and any kickback resulting therefrom. The novel automatic hood guard is releasably mounted at the upper end of the spreader, the spreader having a plurality of openings 28 for receiving a locking pin, as hereinafter described.

The automatic hood guard consists of two parallel plates Z9, 30 having cylindrical spacing bosses 3| near their forward ends secured by a connecting screw 3io., and having near their rear ends vertically elongated spacing blocks 32 integral with the plates and connected with each other by a horizontal plate 32a secured by screwsA 32h. A cam linger 33 is mounted at the front of each plate by means of a hinge bolt 34, the ends of the hinge bolts threadedly engaging suitable openings in the side plates. The cam finger 33 is normally adapted to rest on the face of the table and has a tip'35 provided with a cam edge 36Which is engageable with a pin 3l secured to a slide finger 38, the upper end of the slide finger contacting with a cross bar 39 integral with a second slide finger 40, both fingers being housed for vertical sliding movement in a bracket 4I fastened to the side of the plate, the bracket having a vertical internal shoulder 42 intermediate its width forming resultant vertical channels 43 to guide the movement of the slide fingers, the latter being movable synchronously in an upward direction but capable of successive movement downwardly under the infiuence of gravity, and also having retaining studs 4 la which seat in vertical grooves 42a, in the slide fingers to lock the slide fingers .in place.

The rear end of each plate is similarly equipped with a cam nger 44 which is also hinged to 40n the side plate by means of a hinge bolt 45, and has a tip 46 normally resting on the face 'of the table, with an upper cam edge 4l engageable with a pin 48 on .a rear slide finger 49, the upper edge of the slide finger 49 contacting with a cross bar 50 attached to a second slide 'finger 5|, both slide fingers being housedk for vertical movement in a retaining bracket 52 secured to the side plate, the retaining bracket having a vertical internal shoulder 52a which forms channels 53 for receiving the slide ngers, Vand retaining studs which cooperate with vertical channels in the slide fingers, as for the front slide fingers, to lock the slide :lingers in the bracket channels. The table engaging ends of the cams and slide fingers are preferably rounded.

Locking mechanism for kreleasably attaching the automatic hood guard to the spreader is positionedintermediate the side plates, and Vccnsists of two arms 55, 56 which have hubs at their lower ends pivotally mounted on a cross pin 51 secured to the two plates, the arm 55 having a pin 58 at the end thereof and the arnrt` having a slot 59 at the end thereof, the pin 58 being adapted to be inserted through and extend beyond one of the openings 28, and the slot `59 being adapted to fit over the. end of the pin. The arm 56has two spacer supports 60, 6Ir through which a manually slidable rod 62 extends as illustrated, a compression spring 63 being positioned intermediate the support flanges to cooperate with a cross pin 64 extending through the rod 62v so as to normally urge the locking rod to extended position, the arm 55 having a flange 65 provided with an opening 6G for receiving the extended end of the locking rod, whereby the positioning of the end of the locking rod in the opening 66 releasably locks the two arms 55 and 56 in parallel arrangement to thus retain the pin 58 in the opening 28. Two dogs 61 and 58 are pivotn ally mounted on the ends of the arms 55 and 55, and are balanced so as to have their maximum weight below the pivot point, the lower ends of the dogs being cut so as to present sharp points forwardly for digging into the work as hereinafter explained.

The operation ofthe automatic saw guard may now be explained, with particular reference to Figs. '1, 8, and 9. As the work is advanced towards the saw, the front edge of the work engages the front cam fingers, lifting the cam fingers andthe front slide fingers as a unit, the cam and slide fingers functioning as a fence prior to engagements of the work with the cam fingers so as to prevent any movement of the operators fingers towards the front portion of the saw. As the `work advances during the 'sawing operation, the cam and slide fingers ride on the upper surface of the work, the hood moving upwardly on the lock pin if the work is high. As the work advances further, the points of the dogs ride on the surface of the work and are thus placed in gripping position so as to prevent any rearward movementrof the work; the rear cam fingers are engaged and move upward, simultaneously lifting the rear slide fingers, the rear cam and slide fingers normally functioning as a fence to prevent any insertion of the fingers of the operator towards the rear saw teeth. As the work advances further, the front cam fingers and the front slide fingers are successively released and drop to the table, thus protecting the fingers of the operator; the rear cam and slide fingers are then successively released and drop to the table so as to prevent any contact of the operators fingers with the rear endl of the saw. Althoughk the front cam and slide fingers are successively released, it has been found preferable to so shape the rear cam nger that the reary cam and the first slide finger are simultaneously released, the second rear slide finger then dropping.

While I have described and illustrated a preferred embodiment of my invention, changes in the' size, in the relative proportion of the parts, in their arrangement, and in the material used for the parts, maybe made to suit the requirements for different saw mechanisms, within the spirit and the scope of the' invention as defined in the appended claims.

I claim: l

p l. In a.A saw guard, side members positioned to receive a saw therebetween, slide elements mounted'for sliding movement in said side members, andY means engageable bythe work lfor lifting said'slide elements in unison, said slide elements being successivelyA released upon passage of the work past the slide elements, Y

2. In a saw guard, side members positioned to receive a saw therebetween, slide elements mounted for sliding movement in said side members, and means engageable by the work 'for lifting said slide elements in unison, said slide elements being successively released to fall by their own weight upon passage'of the Work past the slide elements.

3. In a saw guard, a hood comprising side members positioned to receive a saw therebetween, finger guards 'including a plurality of 'slide elements mounted for sliding movement in the side members, means responsive to forward movement of the work to simultaneously lift said slide elements, said slide elements being successively returned to their initial position upon passage of the work therebeyond. l I

4. In a saW guard, a hood comprising side members positioned to receive a saw therebetween,`

nger guards including a plurality of slide elements mounted for sliding movement in the side members at each end thereof, means responsive 5. In a saw guard, a'hood having side members positioned to receive a saw therebetween, a group of slide elements at each end of the side members, cam elements pivotally mounted at each end of the side members each cooperating with a group of slide elements, and adapted to be lifted by contact of the work therewith, and means for moving each group of slide elements upon lifting of their associated cam element, said slide elements being successively returnedto their initial position upon passage of the work therebeyond.

6. In a saw guard, a hood having side members positioned to receive a saw therebetween, a group of slide elements at each end of the sidemembers, cam elements pivotally mounted at each end of the side members each cooperating with a group of slide elements, and adapted to be lifted `by contact of the work therewith, and means whereby lifting of the associated cam element moves one slide element to in turn move a second slide element, said slide elements being sucy cessively returned to their initial position upon passage of the work therebeyond.

7. In combination, a hood guard support having an opening, a hood guard, releasable'locking means on said hood guard comprising two pivoted elements, a laterally extending pin on one element, a slot on the other element adapted to seat in said support opening, and means for releasably lockingl said elements with said pin extending into said slot.

8. In combination, a hood guard support having an opening, a hood guard, releasable locking means on said hood guard comprising two pivoted elements, a laterally extending pin on one element, a slot on the other element adapted to seat in said support opening, and means for releasably locking said elements with said pin extending into said slot, said means comprising a catch member on one element and a latch member releasably engageable therewith on the other element.

9. In combination, a hood guard support having an opening, a hood guard, releasable locking means on said hoodguard comprising two pivoted elements, a laterally extending pin on one element, a slot on the other element adapted to seat in said support opening, and means for releasablylocking said elements with said pin extending into said slot, said means comprising an opening in one member, and a spring pressed bar releasably engageable therewith.

WILLIAM D. DRUMMOND. 

